CVE-2024-50071 in Linux
Summary
by MITRE • 10/29/2024
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: nuvoton: fix a double free in ma35_pinctrl_dt_node_to_map_func()
'new_map' is allocated using devm_* which takes care of freeing the allocated data on device removal, call to
.dt_free_map = pinconf_generic_dt_free_map
double frees the map as pinconf_generic_dt_free_map() calls pinctrl_utils_free_map().
Fix this by using kcalloc() instead of auto-managed devm_kcalloc().
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability CVE-2024-50071 represents a critical double free error in the Linux kernel's pinctrl subsystem, specifically affecting the nuvoton driver implementation. This issue occurs within the ma35_pinctrl_dt_node_to_map_func() function where memory management conflicts lead to potential system instability and security risks. The flaw demonstrates a fundamental misunderstanding of memory allocation and deallocation patterns within the kernel's device management framework, creating a scenario where the same memory region gets freed twice during the device removal process.
The technical root cause stems from improper memory management practices where the developer uses devm_kcalloc() to allocate memory for 'new_map' while simultaneously relying on the automatic cleanup mechanism provided by devm_* functions. The device management subsystem automatically handles memory deallocation when devices are removed, but this automatic cleanup conflicts with the explicit call to pinconf_generic_dt_free_map() which internally invokes pinctrl_utils_free_map(). This dual cleanup mechanism results in the same memory block being freed twice, leading to memory corruption and potential arbitrary code execution. The vulnerability falls under CWE-415, which specifically addresses double free conditions in memory management, and represents a classic example of improper resource management in kernel space.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation and denial of service attacks. When the double free occurs, it can corrupt the kernel's memory management structures, allowing attackers to manipulate the system's memory layout or potentially execute malicious code with kernel privileges. The attack surface is particularly concerning as it affects the pinctrl subsystem which is fundamental to device pin configuration and management across embedded systems and SoC platforms. This vulnerability affects systems using nuvoton pinctrl drivers, particularly those implementing the ma35 series of controllers, making it relevant to a wide range of embedded devices including IoT appliances, industrial controllers, and automotive systems where such drivers are commonly deployed.
Mitigation strategies for CVE-2024-50071 require immediate kernel updates from vendors to apply the patched implementation that correctly uses kcalloc() instead of the auto-managed devm_kcalloc(). The fix addresses the fundamental memory management conflict by removing the automatic cleanup mechanism for the specific allocation, allowing the explicit free function to handle memory deallocation properly. System administrators should prioritize patching affected systems, particularly those running embedded Linux distributions that utilize nuvoton pinctrl drivers. Additionally, implementing runtime monitoring for memory corruption patterns and maintaining up-to-date security patches aligns with ATT&CK technique T1068, which focuses on exploiting vulnerabilities in privileged processes. The fix also reinforces proper adherence to kernel memory management best practices as outlined in the Linux kernel documentation, ensuring that device management functions properly distinguish between automatic and explicit memory cleanup operations. Organizations should also conduct vulnerability assessments to identify systems running affected kernel versions and ensure comprehensive testing of the patch in their specific deployment environments to prevent potential regressions.